Society: SSAT

Background: To address the persistent ethnoracial and socioeconomic disparities in access to quality surgical cancer care, it is imperative to rigorously understand the role of clinician-level factors including clinician-to-clinician connectedness. For patients with gastric cancer, the pathway from primary care (PC) clinicians to gastroenterologists (GI) to cancer specialists (medical oncologists or surgeons) is referral-dependent and requires significant care coordination. However, the impact of clinician-to-clinician connectedness on access to quality gastric cancer surgical care, such as at National Cancer Institute-Designated Cancer Centers (NCI-CC), remains underexplored. This study evaluates how the connectedness between PC clinician or GI with cancer specialists at NCI-CC can influence receipt of gastrectomy for gastric cancer at NCI-CC.

Methods: Maryland’s All-Payer Claims Database was used to evaluate 667 patients who underwent gastrectomy for cancer from 2013-2018. Clinician-to-clinician connectedness was measured via referral linkages between clinicians. Two separate referral linkages, defined as ≥9 shared patients between two clinicians, were examined from: 1) PC clinicians to GI at NCI-CC and 2) GI to cancer specialists at NCI-CC. Multiple logistic regression models were used to determine associations between referral linkages and adjusted odds of undergoing gastrectomy at NCI-CC.

Results: Only 15% of gastric cancer surgeries were performed at NCI-CC. Patients treated by GI with stronger referral links to cancer specialists at NCI-CC were more likely to be <65 years of age, male, white, and privately insured (for all, p< 0.05). Every additional referral link between PC clinician and GI at NCI-CC and between GI and cancer specialists at NCI-CC increased the odds of receiving gastric cancer surgery at NCI-CC by 71% and 26%, respectively (Table). Black patients had half the odds as white patients in receiving gastrectomy at NCI-CC (OR: 0.53, CI:[0.30, 0.93]). However, adjusting for covariates including clinician-to-clinician connectedness weakened the observed negative effects of black race on receipt of gastrectomy at NCI-CC (OR: 0.63, CI:[0.10, 3.83]).

Conclusion: Patients of clinicians with low clinician-to-clinician connectedness and black patients are less likely to receive gastrectomy at NCI-CC. Clinician connectedness appears to be an actionable area of intervention to overcome existing disparities in access to quality surgical cancer care. These results are relevant to policy makers, healthcare systems, clinicians, and patient advocates seeking to achieve equitable access to quality cancer care.

Objective
Computed tomography (CT) imaging routinely detects incidental findings, including hiatal hernias. We utilized a natural language processing algorithm to identify incidental hiatal hernias, characterize their natural progression, and evaluate clinical follow-up.

Methods
Imaging of adult trauma patients from 2010-2020 who underwent CT chest and/or abdomen/pelvis was evaluated using an open-source natural language processor query for hiatal hernias. Patients who underwent subsequent imaging, endoscopy, fluoroscopy or operation were retrospectively reviewed.

Results
1,087 of 10,299 patients (10.6%) had incidental hiatal hernias: 812 small (74.7%) and 275 moderate/large (25.3%). 224 patients (20.7%) had subsequent imaging or endoscopic evaluation, with a mean follow up of 2.78 ± 2.79 years. Patients with moderate/large hernias were older (small vs moderate/large: 66.3±19.4 vs 79.6±12.6 years,p<0.001) and predominantly female (small vs moderate/large: 403[49.6%] vs 199[72.4%],p<0.001). Hernia size was not associated with hernia growth (small vs moderate/large: 13[7.6%] vs 8[15.1%],p=0.102) or symptomology (small vs moderate/large 55.6% vs 67.9%,p=0.110) (Table.1). Though patients with moderate/large hernia were more likely to have an intervention/referral (small vs moderate/large 6[3.5%] vs 7[13.2%], p=0.008), more than 80% of symptomatic patients (n=28) with moderate/large hernias had no follow-up. No patients underwent elective or emergent hernia repair. Three patients had surgical referral; however, only one was seen by a surgeon. One patient death was associated with a large hiatal hernia.

Conclusions
We demonstrate a novel utilization of an NLP to identify patients with incidental hiatal hernia in a large population, and found a 10.6% incidence with only 1.2% of these receiving a referral for follow-up. While most incidental hiatal hernias are small, moderate/large hernias have very high risk of loss-to-follow up and need referral pipelines to improve patient outcomes.

Introduction
The early and swift spread of COVID-19 not only significantly impacted access to healthcare for elective, subacute and acute medical conditions across the US, but also resulted in associated worse outcomes in patients with COVID-19 undergoing procedures compared to pre-pandemic estimates. Additionally, hospital understaffing resulted in increased rates of staff burnout, near misses, and other adverse outcomes. The aim of this study was to explore the use and outcomes of inpatients undergoing Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) in the early months of the COVID-19 pandemic.

Methods
A retrospective observational study was conducted using the National Inpatient Sample for 2020. All patients with RYGB and SG ICD-10 codes were included. The primary outcome was the monthly inpatient odds of RYGB and SG compared to pre-pandemic Jan. Secondary outcomes were monthly inpatient odds of mortality, morbidity and resource utilization comparing these groups. The month of Jan (pre-pandemic) was used as the comparator month for all outcomes. Multivariate regression was used to adjust for gender, age, insurance status, Charlson Comorbidity Index, income in patient zip code, hospital region, location, size and teaching status.

Results
A total of 173,505 patients who underwent bariatric surgery were identified, of which 62,840 (36.22%) were RYGB. Mean age was 45.1 and 79.3% were female. For the primary outcome, there were significantly lower odds of both RYGB and SG in the months of Mar, Apr and May compared to pre-pandemic Jan. This reflects a dramatic drop in monthly procedures from Jan vs Apr of 5,295 to 1,050 (RYGB) and of 9,600 to 275 (SG). Odds for both procedures were significantly increased in the following months from Jun to Dec when compared to Jan. The odds of inpatient mortality for RYGB were not significantly different throughout the year, while they were significantly higher in the month of Apr for SG (N=10 mortalities for April). Increased odds of morbidity and healthcare utilization measures were also evident in both procedures for the month of Apr compared to Jan (pre-pandemic). All results are displayed in Table 1 and 2.

Conclusion
Performance of bariatric surgical procedures in the US was significantly negatively impacted by the COVID-19 pandemic, particularly in the months of March, April and May. Not only did the procedural volumes “recover” in the following months, but a seemingly “compensatory increase” was seen, as reflected by increased procedural volumes from June-December as compared to January (pre-pandemic). Despite the dramatically lower procedural volumes for the month of April, increased odds of post-procedural morbidity measures were noted for patients undergoing both RYGB and SG in that month. This could be due to several reasons, including staffing, patient acuity, and altered work flows.

Introduction: The proportion of women surgeons is steadily increasing, although the number of women in surgical leadership and research has not. The Society for Surgery of the Alimentary Tract (SSAT), a global association of academic gastrointestinal surgeons, pledged its commitment to diversity and inclusion with the creation of a task force and diversity symposium in 2016. Our study sought to evaluate the temporal trend of gender representation in leadership and research presented at SSAT.
Methods: Publicly available SSAT meeting programs from 2010-2022 were reviewed to assess gender proportions within leadership positions (officers and committee chairs), invited speakerships moderators and speakers, clinical symposium moderators and speakers, committee panel session moderators and speakers, and contributions to scientific sessions (moderator, first author and senior author). Verified individual professional profiles (eg, LinkedIn, Doximity, affiliate institution websites) were analyzed to categorize gender as women, men, or not available. Identification of sex was deferred. Descriptive and trend analyses using linear regression and chi-squared testing were performed.
Results: A total of 5,493 individuals were reviewed, of which 1,182 (21.5%) were identified as women and 4,113 (74.7%) as men. 209 (3.8%) did not have an available gender profile. The trend in total women participation is demonstrated in Figure 1 with an increase of 1.04% per year (R²=0.81), comparable to published US trend on active women surgeons. There was a statistically significant difference in the total proportion of women engagement before and after the task force creation in 2016 (18.6% vs 27.1%, p<0.0001), although the increase was 1.93% per year (R²=0.96) prior to 2016 compared to 1.15% (R²=0.64) after. When analyzed by category, annual increases in the proportion of women were demonstrated in: leadership (2.22%, R²=0.50), invited speakerships (2.11%, R²=0.46), invited speakerships moderators (1.35%, R²=0.16 ), clinical symposium moderator (1.25%, R²=0.37), clinical symposium speaker (2.09%, R²=0.63), committee panel session moderator (2.81%, R²=0.25), scientific session moderators (1.06%, R²=0.25), There was no increase seen in committee panel session speakers (0.51%, R²=0.01). 1,595 abstracts were reviewed, with an increase in proportion of first author (1.18%, R²=0.42), but no change in the proportion of women senior author (0.02%, R²=0.00).
Conclusion: There has been an encouraging upward trajectory in women participation at SSAT over the past 13 years. However, if persistent at the current trend, gender parity will not be attained until 2044. Active promotion of gender diversity through creation of a task force or annual diversity symposium, as modeled by SSAT, is an effective tool to improve gender parity, but substantial opportunity for improvement remains.

Trend in total participation of women and non-women (men and not avaliable) at SSAT as well as Association of American Medical College (AAMC) national data on proportion of active surgeons who are women.

Trend in total participation of women and non-women (men and not avaliable) at SSAT as well as Association of American Medical College (AAMC) national data on proportion of active surgeons who are women.

Background
Endoscopic sleeve gastroplasty (ESG) is an innovative minimally invasive bariatric procedure that has shown to be effective in achieving appropriate weight loss in moderately obese patients. It is a safe procedure with few adverse events documented. The steps to perform an ESG have been described by individual endoscopists performing this procedure, however, a true consensus of how to complete an ESG has not yet been established. This study will focus on establishing those steps with a panel of experts.

Method
The Modified Delphi Method was used with the goal of establishing the key procedural steps of an ESG. A panel of 8 experts was selected of which 6 participated. The panel was selected based on their experience with performing the procedure and consisted of 1 bariatric surgeon and 5 interventional gastroenterologists. A neutral facilitator was designated and produced a skeletonized initial version of the key steps that was sent to each of the experts. Each survey began with the experts rating the given steps on a Likert scale of 1-5, with 1 being the most inaccurate and 5 being the most accurate. The final product was also rated. The survey continued with open-ended questions designed to revise and polish the key steps. Areas of discrepancy were addressed with binary questions and majority vote. Respondents were given 10 days to complete each survey. At the end of each round, the survey was then redistributed with updated key steps and questions. This process was continued for a predesignated three rounds.

Results
Of the 8 experts that were queried 6/8, 5/8, and 5/8 replied to each round, respectively. The given ratings for the accuracy of the steps in each round were 4.2, 4.6, and 4.4. The final rating was 4.8. While expert opinion varied around smaller portions of the procedure, such as the placement of an overtube and the shape of each suture line, there was consensus on the need for full-thickness bites and an appropriate swirling of the tissue with the helix device. Whether or not to include the fundus in the gastroplasty was an additional area of discrepancy. 4/5 of the experts agreed that the fundus should remain intact. The final protocol consisted of 20 steps curated from the summarized responses of the experts (Table 1).

Conclusion
Using the Modified Delphi method, we have described 20 key steps to a safe, effective ESG. Establishing the key steps to the ESG will standardize performance across institutions and practitioners. Furthermore, these findings allow for the generation of educational assessment tools to facilitate training and increase the adoption of ESG by endoscopists.

Background: Anastomotic leakage (AL) represents a frequently occurring postoperative complication in colorectal surgery. Scientific efforts have been taken to study the gastrointestinal (GI) anastomotic stability and pressure resistance using various ex-vivo models, however, these often reveal a lack of comparability and reproducibility of scientific data. We therefore aimed to develop an ex-vivo test-setup for quantitively precise determination of the GI-anastomotic quality in terms of stability and pressure resistance with high comparability, reproducibility, and user-independence and thus to increase the understanding of the biomechanics of anastomoses and AL.
Methods: An open fluid circulation system based on a modified perfusion bioreactor, using a human machine interface, was developed to transport colored phosphate-buffered saline (PBS) at constant flow rate (low flow-model (LF) or high flow-model (HF) simulating physiological and increased intraabdominal pressure (IAP)) intraluminal into a porcine small intestinal anastomosis after passing a pressure probe. While measuring the intraluminal pressure and temperature of the surrounding PBS, different cameras record each angle of the anastomosis. Overall, 32 end-to-end anastomoses (EEA) (16 single button suture (SBS) and 16 continuous suture (CS)) on native small intestinal tissue were tested using two different flow rates (LF and HF). Maximum pressure was recorded and defined as the bursting pressure (BP).
Results: The new developed ex-vivo test-setup for determination of the GI-anastomotic stability was identified as a precise technique to evaluate stability and pressure resistance of GI-anastomoses. The application of the test setup resulted in precise and highly reproducible data that allowed reliable comparison between different techniques of GI- anastomoses (e.g., HF CS-EEA: 95% confidence interval (CI), 144.74–193.76; HF SBS-EEA: 95% CI, 136.11–191.89). Analysis of LF and HF SBS-EEA as well as LF and HF CS-EEA showed a significant difference in BP between the groups LF vs. HF. HF SBS-EEA and HF CS-EEA revealed a higher BP compared to LF SBS-EEA and LF CS-EEA (LF and HF SBS-EEA: mean difference (MD), 74.25 mmHg; 95% CI, 20.49–118.01 mmHg; p=0.010; LF and HF CS-EEA: MD, 90.125 mmHg; 95% CI, 57.17 –123.04 mmHg; p <0.001).
Conclusions: The innovative ex-vivo model for quantitively precise determination of the GI-anastomotic quality in terms of stability and pressure resistance presented a high comparability, reproducibility, and user-independence. The significant difference observed between LF and HF anastomoses support the biomechanism of time-dependent response of intestinal tissue as the stress-strain response didn’t occur instantly. The application of this innovative model may pave the way for the development of new anastomotic techniques possible reducing AL, without animal testing.

Introduction: The urokinase-plasminogen system is a well-known promoter of colorectal cancer (CRC) progression. Its end-product, plasmin, mediates submucosal collagen degradation, chemotaxis, angiogenesis and growth factor release in the tumor microenvironment. We have previously demonstrated that selective gut pathogens, specifically, collagenase producing Enterococcus faecalis, that are known to overgrow during states of dysbiosis, can induce CRC invasion and migration in vitro and in vivo. In the present report we hypothesized that E. faecalis promotes increased plasmin production in cancer cells. Therefore the aim of this study was to demonstrate that co-incubation of CT26 colorectal cancer cells with collagenase producing E. faecalis increases their plasmin production.

Methods: 4 X 10⁴ CT26 colorectal carcinoma cells and collagenolytic E. faecalis strain V583 were utilized for all experiments. After co-incubation of E. faecalis and CT26 cells, fluorescently labeled plasminogen (PLG) was added for two hours and PLG binding measured by fluorimetry after washing. Fluorogenic plasmin generation assays were used to measure the kinetics of PLG activation. Tranexamic acid (TXA), a small molecule, was used to inhibit PLG activation.

Results: Co-incubation of E. faecalis with CT 26 cells for 24 hours resulted in a significant increase in binding of PLG to CT26 cells compared to when E. faecalis was absent (Panel A - CT26 alone: 4.1+/-0.1*10⁵ RFU vs CT26+EF 24hr 6.9+/-0.8*10⁵ RFU, *p<0.05). This binding was not demonstrated during coincubation at 6 hours. The presence of E. faecalis resulted in a striking increase in active plasmin with a four-fold increase in activity at a multiplicity of infection (MOI) of 10 compared to when E. faecalis was absent (Panel B - CT26 alone: 1.7+/-0.1*10⁴RFU/s vs CT26+EF MOI 10: 6.8+/-0.1*10⁴ RFU/s, *p<0.05) or at a MOI of 1. Tranexamic acid inhibited E.faecalis- induced PLG activation by CT26 cells in a concentration-dependent fashion (Panel C, *p<0.05).

Conclusions: E. faecalis induced cell surface binding of PLG to CT 26 cells and increased their activation of the growth-promoting enzyme plasmin. Given the central role of plasmin in cancer cell progression, further investigation into the role of bacterial-mediated PLG activation of CRC progression is warranted.

Introduction: Short esophageal length has been proposed as a risk factor for paraesophageal hernia (PEH) recurrence. We sought to investigate the relationship between pre-operative manometric measurements of esophageal length or a calculated manometric esophageal length to height ratio (MELH) and recurrence in primary PEH repair. We hypothesized that intraoperative high mediastinal esophageal mobilization is sufficient to gain adequate intraabdominal esophageal length for PEH repair, and pre-operative shortened esophageal length does not increase the risk of recurrence.

Methods: Patients who underwent elective PEH repair between 2015 and 2022 at a university-based hospital were identified. Patients who had prior esophageal or gastric surgery or did not have pre-operative manometry were excluded. Patient demographics, operative details, pre-operative manometric esophageal length, and radiographic or symptomatic PEH recurrence were recorded in an IRB-approved database. The MELH was calculated as manometric esophageal length divided by height in cm. Descriptive statistics and logistic regression were used to analyze the data. Data are presented as mean±SD or median [IQR] and p-values of <0.05 were considered statistically significant.

Results:
Of the 160 patients (mean age 66.4±8.9 years, 78.8% female) who underwent elective PEH repair during the study period, 30.6% (n=49) had a PEH recurrence. Amongst those with recurrences, 32.7% (n=16) were symptomatic and 67.3% (n=33) were radiographic. Radiographic recurrence was found in 36.3% (n=91) of patients who had interval imaging for any reason. A total of 7.5% (n=12) of patients required a reoperation for recurrence. With a median follow-up of 20.0 [2.2, 39.1] months, the median time to recurrence was 10.1 [4.4, 21.7] months. All patients underwent a high mediastinal mobilization to achieve intraabdominal esophageal length of at least 2-3cm; no patients underwent esophageal lengthening gastroplasty. Average manometric esophageal length was 19.7±2.7cm (range: 12.1-28.1cm). Average MELH was 0.119±0.014 (range 0.079-0.152). Neither manometric esophageal length nor MELH was associated with radiographic or symptomatic PEH recurrence (Table 1), and neither manometric esophageal length nor MELH correlated to time to recurrence (p>0.05).

Conclusion:
Pre-operative manometric esophageal length and manometric esophageal length to height ratio are not correlated with either symptomatic or radiographic paraesophageal hernia recurrence in elective, primary paraesophageal hernia repair. In addition, incidentally identified recurrence is very common and occurs in over a third of patients who have interval imaging. Our findings suggest that high mediastinal esophageal mobilization achieving adequate intraabdominal esophagus is sufficient to overcome short esophageal length found on pre-operative manometry.

Introduction: Mental illness (MI) and suicidal ideation (SI) are often associated with a diagnosis of cancer and may contribute to suboptimal outcomes. We sought to define the incidence of MI and SI among patients with gastrointestinal cancers, as well as ascertain patient, clinical, and social determinants of health (SDoH) that were associated with SI.

Methods: Patients diagnosed between 2004-2016 with stomach, liver, pancreatic, and colorectal cancer were identified in the Surveillance, Epidemiology, and End Results-Medicare linked database. County-level social vulnerability index (SVI) was determined using the Centers for Disease Control/Agency for Toxic Substances and Disease Registry, while the Area Health Resource Files were utilized to determine the number of mental health professionals available per 1,000 population. Data was analyzed relative to MI or SI, and multivariable analyses were used to identify factors associated with SI.

Results: Among 382,266 patients (stomach: n=38,430, 10.1%; liver: n=42,393, 11.1%; pancreas: n=68,818, 18.0%; colorectal: n=232,625, 60.9%), 83,514 (21.9%) individuals had a diagnosis of MI (depression: n=25,786, 6.7%, anxiety: n=17,369, 4.5%; depression + anxiety, n=14,375, 3.7%; bipolar disorder, n=11,831, 3.1%; other MI, n=14,153, 3.7%). Overall, 1,410 (0.37%) individuals experienced SI and 359 (0.09%) committed suicide. Compared with patients not receiving active cancer treatment, individuals receiving treatment had an increased risk for SI (OR 1.40, CI 1.17-1.66; p<0.001). Interestingly, SI was least likely among patients with pancreatic cancer (ref: liver cancer; OR 0.67, CI 0.52-0.86; p=0.002), as well as patients with stage III/IV disease (ref: stage I/II; OR 0.59, CI 0.52-067; p<0.001). In contrast, factors most strongly associated with increased SI risk included male sex (OR 1.34, 95% CI 1.19-1.50), White race (OR 1.34, CI 1.13-1.59), and single marital status (OR 2.03, CI 1.81-2.28)(all p<0.001). Of note, compared with patients who resided in counties with high social vulnerability, individuals living in ares with lower SVI had markedly higher risk of SI (OR 1.33, CI 1.14-1.54; p<0.001) (Figure). In addition, living in a county with a shortage of mental health professionals was associated with increased odds of developing SI (OR 1.21, CI 1.04-1.40; p=0.012).

Conclusion: Roughly 1 in 5 patients diagnosed with a gastrointestinal cancer had a MI diagnosis, most often including depression or anxiety. A subset of patients experienced SI with single, white males who lived in areas of relative privilege being most likely to experience SI. Oncology care teams should incorporate routine mental health and SI screening when treating patients with gastrointestinal cancers, and target suicide prevention to those populations at highest risk.

<b>Figure</b>: Predicted probabilites of (a) mental illness and (b) suicidal ideation, relative to social vulnerability index and stratified by race

Figure: Predicted probabilites of (a) mental illness and (b) suicidal ideation, relative to social vulnerability index and stratified by race

Purpose
This study aims to evaluate the influence of institutional total gastrectomy (TG) volume for patients with gastric cancer on the short-term outcomes and costs in the Brazilian public health system.

Methods
This population-based study evaluated the number of surgical procedures performed by institutions in the Brazilian Public Health system from 2008 to 2021. Data were extracted from public domain from the informatic departments of the Brazilian public health system (DATASUS).
We include the SUS Procedures, Medicines, and OPM Table Management System (SIGTAP) identifiers ‘Total Gastrectomy’ (04.07.01.014-9) and ‘Total Gastrectomy in Oncology’ (04.16.04.007-1). All hospitals supported by the SUS were included. Costs were expressed in US dollars, considering $1,00 = R$ 5,19 as of November 2022.

Results
Six hundred and sixty-six hospitals performed total gastrectomy for patients with gastric cancer between 2008 and 2021 in Brazil. The total number of hospitalizations was 18.466 (mean age 61.3; 64.3% male), with 1.716 in-hospital deaths. The highest number of procedures was recorded in the Brazilian Southeast region, responsible for 51% of the procedures. Total costs were U$ 19.052.371,12. The linear regression model showed that the number of hospital admissions for TG was negatively associated with hospital mortality (Coef -.323; p<0.001).
Only 24 hospitals performed at least 10 TG per year and were considered high-volume institutions. These hospitals were responsible for 6.161 procedures, while low-volumes (<10 TG per year) perfomed 11.262 TG. In-hospital mortality for high-volume institutions was significantly lower than for low-volume institutions (7.8% vs. 25.4%; mean difference: 17.4%; p<0.001). The mean length of stay in the ICU was also lower in high-volume centers (2.41 vs 1.32 days; mean difference 1.09; p=0.004). Total costs were higher in high-volume hospitals (U$1090,80 vs. U$856,95; mean difference U$235,54; p<0.001).

Conclusion
Institutional TG volume implies lower in-hospital mortality and less demand for intensive care. The findings of this nationwide study can affect how Public Health manages TG care and its resources.

<b>Total Gastrectomies per state from 2008 to 2021 in the Public Health System of Brazil</b>

Total Gastrectomies per state from 2008 to 2021 in the Public Health System of Brazil

Introduction: Gastroesophageal reflux disease (GERD) may present with different patterns (upright, supine, or bipositional). Some studies suggested that supine reflux is clinically more severe. It is elusive; however, if there are differences between daytime versus nighttime supine reflux. Our study aims to compare the characteristics of daytime and nighttime supine reflux assessed by pHmonitoring.
Materials & Methods: We reviewed 472 consecutive patients that underwent esophageal manometry and pH monitoring. Patients were classified as GERD + per DeMeester score > 14.7. Upright acid exposure time (AET) was considered pathologic > 6% and supine AET > 2%. Acid reflux during daytime and nighttime recumbent position were compared. The number of episodes of reflux, AET, longest reflux (minutes), number of long refluxes (>5minutes), interval between last meal and recumbence, the interval between beginning of recumbence and the first episode of reflux and symptoms during recumbence were recorded.
Results: 250 (53%) patients were GERD + (12 (5%) upright, 156 (62%) supine and 41 (16%) bipositional pattern). Recumbence during daytime occurred in 212 (42%) patients, 27 twice and 1 thrice (107 (50%) were GERD+, 87 (41%) with supine pattern). One hundred and fifteen (52%) out of 222 patients that did not present with daytime recumbence were GERD +, 84 (38%) with supine pattern. There was no difference for the presence of GERD (p=0.8), supine pattern (p=0.1) or DeMeester score (p=0.2) between the patients that had a daytime recumbence or not. Table 1 shows the comparison between acid reflux during daytime versus nighttime of all patients. AET was not different between daytime or nighttime recumbence. All other parameters were lower during daytime recumbence. The interval between last meal and recumbence and the interval between from the beginning of recumbence and the first episode of reflux were lower for daytime recumbence. The report of symptoms during recumbence was similar between daytime and nighttime. A subanalysis comparing daytime versus nighttime reflux only among patients that had daytime recumbence (Table 2) showed similar results except for AET that were similar between periods (p=0.3).
Conclusions: Our results show that: (a) daytime recumbence is not a risk factor for GERD; (b) daytime recumbence is not a risk factor for supine reflux; (c) AET is not different from daytime and nighttime recumbence but all other parameters are lower for daytime recumbence even tough patients tend to have a shorter interval between meals and recumbence.

<b>Table 1. Acid exposure parameters for daytime versus nighttime recumbence (all patients n=473).</b>

Table 1. Acid exposure parameters for daytime versus nighttime recumbence (all patients n=473).

<b>Table 2. Acid exposure parameters for daytime versus nighttime recumbence (patients with daytime recumbence n=212).</b>

Table 2. Acid exposure parameters for daytime versus nighttime recumbence (patients with daytime recumbence n=212).

Introduction: Impedance planimetry is gaining popularity as a method of quantifying changes in the distensibility index (DI) of the gastroesophageal junction during anti-reflux surgery. Studies have shown that patients with gastroesophageal reflux disease (GERD) have higher baseline DI compared to controls. However, these measurements may differ depending on patient and procedural variables. In this study, we sought to further quantify changes in DI with increasing impedance planimetry balloon-fill volumes (BV) in patients with GERD and to identify patient factors contributing to preoperative DI.

Methods: A retrospective review of a prospectively maintained anti-reflux surgery database was conducted between 2021-2022, including patients who underwent hiatal hernia repair and fundoplication with preoperative impedance planimetry.

Results: 61 patients underwent anti-reflux surgery with impedance planimetry at multiple BVs. A subset of 10 patients underwent measurements with increasing BV by 5mL increments, ranging from 10mL to 50mL, with the remaining patient measurements obtained sequentially at 30, 40, and 50mL. All measurements were obtained post-induction in the supine position prior to abdominal insufflation. In patients undergoing 5mL incremental increases in BV, DI significantly increased with increasing volume ranging from a median DI of 2.0 (IQR 1.63-2.36) at 10mL BV to 3.62 (IQR 2.35-6.05) at 50mL BV (p=0.03). In the cohort of patients evaluated at 30, 40 and 50mL of BV, there was a plateau effect with no significant difference in median DIs of 2.69 (IQR 1.63-4.50), 2.81 (IQR 1.84-4.60), and 2.88 (IQR 2.06-4.66) (p=0.64). To further investigate factors contributing to preoperative DI, univariate analysis was performed examining patient factors including age, sex, BMI, manometric results, symptom profiles, and barium swallow findings while controlling for balloon-fill volume. The presence of atypical GERD symptoms was associated with lower DI (β=-1.30 p=0.038), while the presence of hiatal hernia on barium swallow was predictive of increased DI (β=1.11 p=0.028). Age, sex, BMI, and manometry findings were not associated with changes in DI.

Conclusion: While preoperative distensibility index does appear to increase with balloon-fill volumes ranging from 10mL to 50mL, values measured at the BVs used in clinical practice (30, 40, and 50mL) do not significantly differ from one another. Factors found to contribute to preoperative DI included the presence of hiatal hernia on barium swallow and the presence of atypical GERD symptoms. Further research is needed to correlate patient factors with DI, allowing for improved interpretation of results and application in clinical practice.

Abhinay Tumati

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